library(ggplot2)
climate <- read.table("clim.txt", header=T)
climate$date <- NULL
clim_month <- aggregate(rain~year+month, data = climate, FUN = sum)
ggplot(clim_month, aes(group=month, x = month, y = rain)) +
  geom_boxplot(fill = "cyan") +
  scale_y_continuous(name = "Total Monthly Precipitation") +
  theme_bw()+
  theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank())+
  scale_x_continuous(name = "Month", breaks = c(1,2,3,4,5,6,7,8,9,10,11,12))

Figure 1. Boxplot of average monthly precipitation based on data from years 1942-2016.

clim_temp_min <- aggregate(tmin~month+year, data = climate, FUN = mean)
clim_temp_max <- aggregate(tmax~month+year, data = climate, FUN = mean)
clim_temp <- merge(clim_temp_max, clim_temp_min)

ggplot(clim_temp, aes(group= month, x = month)) +
  geom_boxplot(aes(y=tmax), fill = "orange") +
  geom_boxplot(aes(y=tmin), fill = "lightskyblue1") +
  scale_y_continuous(name = "Average Min and Max Temperatures (C)") +
  theme_bw()+
  theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank())+
  scale_x_continuous(name = "Month", breaks = c(1,2,3,4,5,6,7,8,9,10,11,12))

Figure 2. Shows average monthly temperatures (°C), where average highs are shown in orange, and lows shown in blue.

clim_rain <- aggregate(rain~year, data = climate, FUN = sum)
ggplot(clim_rain, aes(y = rain, x = year))+
  geom_line(stat = "identity", color = "blue", size = 0.5) +
  theme_bw()+
  scale_x_continuous(breaks=seq(1940, 2020, by = 5))+
  theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank())+
  ylab("Total Annual Precipitation")+
  xlab("Year")

Figure 3.Time series of annual precipitation spanning from 1942-2016

Based on the above, the wettest years were 1982, 1969, 1983, and 1996. The driest years were 2013, 1947, 2016, and 1976.

Wet and dry seasons

range(climate$month)

## [1]  1 12

climate$season = ifelse(climate$month %in% c(3,4,5),"1", ifelse(climate$month%in% c(6,7,8),"2", ifelse(climate$month %in% c(9,10,11),"3", "4")))

clim_season <- aggregate(rain~season+month+year, data = climate, FUN = sum)
ggplot(clim_season, aes(group=season, x = season, y = rain)) +
  geom_boxplot(fill = "cyan") +
  scale_y_continuous(name = "Precipitation") +
  theme_bw()+
  theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank())+
  scale_x_discrete(name = "Season")

Figure 4. Seasonal precipitation where 1 represents spring, 2 summer, 3 fall, and 4 winter. Spring is months March-May, summer months June-August, fall months September-November, and winter months December-February.

seasonal_rain <- aggregate(rain~year+season, data = climate, FUN = sum)
winter_rain<- subset(seasonal_rain, season == 4)
season_temp <- aggregate(tmax~year+season, data = climate, FUN = mean)
summer_temp <- subset(season_temp, season == 2)
rain_temp <- merge(summer_temp, winter_rain, by = "year")

ggplot(rain_temp, aes(x=rain, y= tmax, group_by(year))) +
  geom_point(size=0.8)+
  geom_smooth(method=lm, se = FALSE, formula = y ~ x, color = "blue", size = 0.5)+
  theme_bw()+
  theme(panel.grid.major = element_blank(), panel.grid.minor = element_blank())+
  xlab("Total Winter Precipitation")+
  ylab("Mean Temperature")

Plot showing relationship between winter precipitation and summer temperature

linear_reg <-lm(rain ~ tmax, data=rain_temp)
summary(linear_reg)

## 
## Call:
## lm(formula = rain ~ tmax, data = rain_temp)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -402.56 -167.86  -51.86  156.82 1019.19 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)  
## (Intercept)   986.37     560.93   1.758   0.0829 .
## tmax          -20.48      24.67  -0.830   0.4091  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 263.1 on 73 degrees of freedom
## Multiple R-squared:  0.009355,   Adjusted R-squared:  -0.004216 
## F-statistic: 0.6894 on 1 and 73 DF,  p-value: 0.4091

The relationship between winter precipitation and summer temperature might be useful to know because while the above relationship is not significant there is a slightly negative relationship between winter precipitation and summer temperatures. This may be important particularly in dry years, as warmer temperatures and dry conditions may lead to a significant fire season.